The strike by 100 IT staff at Swansea council about plans to outsource their jobs could escalate after their union, Unison, decided to ballot all its 5,000 members at the council on industrial action.
Unison held a council-wide union meeting and a proposal to ballot all staff for industrial action was carried unanimously, according to one source.
The 100 staff have been on indefinite strike since 16 August and refuse workers have already taken unofficial action to support them.
The council is considering outsourcing the council IT department and its staff to either Capgemini or ITNet as part of the proposed £100m Service@Swansea project.
The type of action to be taken if the ballot results in a "yes" vote has so far not been confirmed, although the strike by the IT workers will continue while the ballot is being run.